Precision quick balance



Feb. 16, 1932. Q SCHMIT 1,845,523

PRECISION QUICK BALANCE Filed Nov. 30. 1929 INV E NTOK... Ofo SCAM/J7 8717650.; Kyu

R TTORNETS,

Patented Feb. 16, 1932 UNITED STATES OTTO SCHMIDT, F BERLIN-TEGEL, GERMANY PRECISION QUICK BALANCE Application filed November 30, 1929, Serial No. 410,692, and in Germany December 3, 1928.

The invention relates to a top pan quick balance serving for the weighing of very small loads down to fractions of grammes, without the use of weights, which have hitli- 6 erto been found tedious and troublesome in the case of beam balances used for line weighing.

The balance is constructed on the principle of the well known automatic balance but with .1.0 the differences representing the essence of the invention, which are characterized by the provision of a scale pan pendulum supported directly in the wide knife edge bearing of the indicator pendulum, in order to give by means of such a top pan arrangement a more convenient use of the balance than with a sus )ended pan.

'lLhe invention is further characterized by the provision of a device for damping or arresting the oscillations of both the indicator pendulum and the pan pendulum, which arresting device releases the pendulums after the damping of the oscillations has taken place, so that said penduluins are free from all contact whatever with any stationary part of the machine. By this construction the use of indicator balances is made possible for precision weighing, for which purpose the well known air and oil cylinder arresters are totally unsuited.

In the accompanying drawings,

Fig. 1 is a side view of a balance embodying the features of the present invent-ion;

Fig. 2 is a front view thereof; and

Fig. 3 is a diagrammatic side view illustrating a modified form of the arresting device.

To an upright a, is fixed a pan bracket 7) which takes, on a Wide bearing, the knife edge axis c of the pendulum d. The knife edge e is fixed on the pendulum al and in the ends thereof is suspended by means of bushes a scale pan pendulum The knife edge for the scale pan has approximately the length of the load field of the scale pan carried thereon, Its points of application, however, do not need to be formed by the ends of a correspondingly long knife edge, but the indicator pendulum may carry in place thereof two short knife edges at a suitable distance apart.

i is a' compensating weight for the scale pan pendulum onay special arm of the indicator pendulum. The scale pan pendulum carries they load weight i which corresponds in its size to the weighing range of the balancel in suchmanner that on placing the highest load on the left hand or right hand edge of the scale pan, the latter can only effect a slight inclination in the plane of oscillation still possible thereto, so that the load when placed at the side cannot slide oil".l

The loading of the oscillatory sca-le pan with its counter weight plays no part in the iineness of the play of the balance as it isV always in proportion to the weighing range of the balance. The arrangement permits, on the other hand, however, atop pan balance as a pure indicator balance, and renders su# perfluous any transmission lever mechanism, such as the generally known quick balances combined with an indicator balance require, the latter not being, capable of use as fine balances in the sense of the present balance.

To the scale pan stabilizing pendulum f are fastened, in the example of construction i shown in Figs. 1 and 2, two oppositely situated arresting plates Ick, between which is arranged a spindle ym, or the like rotatably carried in a bearing bracket Z', the' free end of the spindle carrying in the centre between the arresting plates an approximately S- shaped, very fine spring band zu, which on pressing down the lever 0 fixed on the spindle m ispressed with bothy ends uniformly each againstan arresting plate, causing the dampingof they oscillations ofthe scale pan pendulum f aswell as of the indicator pendulumd. The hand lever 0 is suitably provided with a counter Weight p in order, on the terminationy of-the arresting process, to again swing away the fine steel band or the like from the arresting surfaces: of the plates and to again completely release the balance.

Fig. shows diagrammatically a modified form of the arresting device, in which two spring bandsA n are shownv associated with a single scalecontrolled plate 7c', the dotted position of the elastic arresting bodies representing the most powerful arresting pres- M sure. The powerfulcommencing pressure of the arresting bodies first-moderates the early strong oscillations of the pendulum, and then as they gradually lessen, the finest oscillations until the complete deflection and the re lease of the balance from the iniiuence thereon by the arrester.

The damping of the oscillations above de scribed may be accomplished by means other Y than the application of elastic arresting members, without departing from the spirit and Y scope of the inventiom Patent claims:

1. A precision balance, comprising in combination, a pivoted indicated device, a pendulum vkfor swinging said device on its pivot, a scale pan disposed above said pendulum and pivo-tally supported thereon,a stabilizing pendulum carried by said scale pan, elasticmeans operable to dampen the oscillations of both of said pendulums, and means operative after actuation of said elastic means to return the same to inoperative position.

2. A precision balance, comprising in combination, a pivoted indicating device, a pen dulum for swinging said device on its pivot, y

a scale pan disposed above said pendulum Y and pi-votally supported thereon, a stabilizing pendulum carried by said scale pan, elastic means manually'operabletoV dampen the oscillations of both of said pendulums, and means automatically operable afterv actuation of said elastic means to return the same to inoperative position. Y Y

3,. A precisionbalanc-e, comprising in combination, a pivoted indicatingv device, a pendulum for swinging said device on its pivot, a scale pan disposed .above said pendulum and pivotally supported thereon, a stabilizing pendulum depending from said scale pan, an arresting plate carried by said stabilizing'pendulum, elastic means disposed adja-v cent to said plate, lmeans for moving said elastic lmeans into contact with said plate thereby to dampen the oscillations of both of said pendulums, and means operative after actuationof saidelastic means to return the same to inoperative position.

4. A precision balance, comprising in combination, a pivoted indicating device, a pendulum for swinging said device on its pivot, a scale pan disposed above said pendulum and pivotally supported thereon, a stabilizing pendulum depending from said scale pan, a pair of arresting plates carried by said stabilizing pendulum, a movable member disposed between said plates and having a pair of elastic members disposedadjacent to said plates, manually operable means for moving said member to carry said elastic members into Contact respectively with said plates, and automatically operable means for returning said movable member to its initialposition thereby to carry said elastic members out of contact Withsaid plates.

OTTO SCHMIDT` 

